Pressure-gage.



C. J. MANNING.

PRESSURE GAGE.

APPLICATION HLED OCT. '2, 1914.

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I nivrrn sra I COLEMAN J. MANNING, OF MEDFORD, MASSACHUSETTS, ASSIGNOBTO AMERICAN STEAM GAUGE AND VALVE MANUFACTURING COMPANY, OF BOSTON,MASSA- CHUSETTS, A CORPORATION OF MASSACHUSETTS.

PRESSURE-GAGE.

- Y Application filed October 2,

T 0 all whom it may comm:

Be it known that I. COLEMAN J. MAN- Mr G, a citizen of the UnitedStates, and res ident of Medford, in the county of Middlesex and Stateof Massachusetts, have invented certain new and useful Improvements inPressure-Gages, of which the following is a specification.

This invention relates to a pressure gage comprising a Bourdon springconnected by suitable mechanism with a pointer and adapted to be flexedfrom its normal form by fluid pressure to move the pointer forward overa dial, the pointer being moved backward by the spring when the latterreturns to its normal form.

The invention has for its object to enable the spring and pointer tohave movements of maximum amplitude when the fluid pressure isrelatively low, and movements of lesser or minimum amplitude when thefluid pressure is relatively high,'to the end that relatively lowpressures, which are those more frequently exerted and registered, maybe easily read by the aid of widely spaced graduations on a segmentaldial scale, while higher pressures, which are less frequently exertedand registered, may be read by the aid of more narrowly spacedgraduations on the same dial scale, the length of the scale required forregistering all pressures exerted being reduced to the minimum.

The invention consists in the improvements which I will now proceed todescribe and claim.

Of the accompanying drawings forming a part of this specification:Figure 1 repre sents a front view of a pressure gage embodying myinvention, the dial being in place; Fig. 2 represents a view similar toFig. 1, the dial being removed; Fig. 3 represents a section on line 3-3of Fig.2, showing a portion of the dial; Figs. 1 and 5 representfragmentary views showing modifications of the Bourdon spring abutmenthereinafter referred to; Figs. 6 and 7 are diagrammatic views of thespring and abutment; Fig. 8 represents a view similar to Figs. 4 and 5,showing another modification.

The same reference characters indicate the same or similar parts in allthe views.

In the drawings: 12 represents the case, 13 the Bourdon spring, 14: thedial, and 15 Specification of Letters Patent.

Patented Feb. 1, 1916.

1914. Serial No. 864,612.

the pointer of a pressure gage, which, excepting as hereinafterspecified, is of common and well known construction, the pointer beingmounted on an arbor 16 which is connected with the free end of theBourdon spring by mechanism including a link 17, a lever 18 having asegmental rack 19, and a pinion 20 on the arbor meshing with the rack.Vhen the Bourdon spring is at rest the. pointer is held at the zero markon a segmental scale 21'on the dial, and when the spring is flexedoutwardly by fluid pressure admitted through the nipple 22 the pointeris moved forward over the scale.

In carrying out my invention 1 provide an abutment located in the pathof movement which is imparted to the spring 13 by its outward flexure,said abutment being separated from the spring when the latter is at restor in its normal form and position. As shown by Figs. 2 and 3, saidabutment is a cylindrical stud 23 having an eccentric neck 24 fittedclosely to turn in an orifice in the back of the case, so that a partialrotation of the stud will vary the dis tance between its periphery andthe spring when the latter is at rest, the abutment being rotatable by ascrew-driver engaged with a slot 25 in its outer end, and retained byfriction at any position to which it may be rotated.

The abutment 23 is so arranged that the spring 13 is free to be flexednormally or throughout its entire length to a limited extent before itcontacts with the abutment. During this normal outward flexure, and anyreturn movement caused by the inward flexure of the spring when thepressure decreases the spring moves the pointer 15 over the portion ofthe scale 21 having widely spaced graduations 21 (Fig. 1), pressureregistration being therefore easily read.

When the outward flexure of the spring brings it into contact with theabutment, the effective length of the spring is reduced so thatsubsequent outward fiexure is limited to the portion of the springbetween its free end and the abutment. During this limited flexure andany return movement caused by inward flexure, the spring moves thepointer over the portion of the dial scale having the narrowly spacedgraduations 21", the amplitude of the movements of the pointer caused bygiven variations of pressure being greatly and limited fiexure of thespring 13 to be varied as circumstances may require. F igs. 1- and 5show other forms of adjustable abutment, Fig. 4 showing an abutment 23which is a headed screw engaged with a tapped orifice in a fixed ear 26in the case 12, while Fig. 5 shows an abutment 23 which is a headedscrew engaged with a tapped orifice in the case 12 and provided withlock nuts 27, 28, hearing on the outer and inner sides of the case.

Fig. 6 shows by full and dotted lines the normal flexure of the spring13, and Fig. 7

' shows by full and dotted lines the limited flexu-re of the springcaused by contact 015 the spring with the abutment.

The eccentric neck 24 of the abutment 23 may be fitted closely to turnin an orifice in a fixed plate 30 within the case .12, as shown by- Fig.'8.

between the free end of the spring and the pointer for op'eratingthelatter, an abutment secured to the case in the path of movement of thespring and arranged to permit a limited unobstructed outward movement ofthe spring from its initial position, and

to thereaiiter arrest the outward movement of the inner portion of thespring, leaving only the outer portion fre'e' to "operate the pointer. vI

A pressure ga ge comprising a case, a pointer, a member having one "endfixed and the oth'er end free to move under variations of pressure, thelatter end being connected to the pointer to actuate it, a scale havingits high --inc l-icating graduations closer together than thelow-indicating graduationsfand means-adjacent an intermediate portion ofsaid member to limit the capability of movement of said member, underhigh pressure, to the portion beyond said limiting =means.

In testimony whereof I have affixed signature, in presence of twowitnesses.

GOL'EMAN J.-MANNING-. Vitn'esses G. Brown,

.PEzznTTr.

Copies of this patent may :be obtained for five cents'each, byaddressing the Commissioner of Patents,

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